Just ordered the 21.5". Got the 16 GB of memory and did the processor upgrade. I wanted the fusion option, but started to run out of money. Compared to my six year old, first gen Intel iMac, I'm pretty sure I am going to see a HUGE difference. Now if I could just get a delivery date and hope that the kids understand Christmas is cancelled, everything will be great. I was going to go fusion and upgrade memory later, but I was told it is not upgradeable. Also, my buddy and I are thinking that they are using Laptop drives in the 21's. That is why you can only go to 1TB. Any opinions on this?
Yes they are using laptop drives to fit the form factor and to allow for 1TB. They should've re though the pricing scheme a bit, or offered 500gb 7200rpm 2.5" drives on the 21.5" models. Oh well, whats done is done. I am glad everyone got to order their machines already!